Motion detection is a process of confirming a change in position of an object relative to its surroundings or the change in the surroundings relative to an object. This detection can be achieved by both mechanical and electronic methods. In addition to discrete, on or off motion detection, it can also consist of magnitude detection that can measure and quantify the strength or speed of this motion or the object that created it. Motion can be detected by: sound (acoustic sensors), opacity (optical and infrared sensors and video image processors), geomagnetism (magnetic sensors, magnetometers), reflection of transmitted energy (infrared laser radar, ultrasonic sensors, and microwave radar sensors), electromagnetic induction (inductive-loop detectors), and vibration (triboelectric, seismic, and inertia-switch sensors). Further, acoustic sensors are based on: electret effect, inductive coupling, capacitive coupling, triboelectric effect, piezoelectric effect, and fiber optic transmission. Radar intrusion sensors have the lowest rate of false alarms.
Motion sensors have been utilized in numerous rooms and buildings, including the following:                It is common for stores to have a beam of light crossing the room near the door, and a photosensor on the other side of the room. When a customer breaks the beam, the photosensor detects the change in the amount of light and rings a bell.        Many grocery stores have automatic door openers that use a very simple form of radar to detect when someone passes near the door. The box above the door sends out a burst of microwave radio energy and waits for the reflected energy to bounce back. When a person moves into the field of microwave energy, it changes the amount of reflected energy or the time it takes for the reflection to arrive, and the box opens the door. Since these devices use radar, they often set off radar detectors.        The same thing can be done with ultrasonic sound waves, bouncing them off a target and waiting for the echo.        
All of these are active sensors. They inject energy (light, microwaves or sound) into the environment in order to detect a change of some sort. The “motion sensing” feature on most lights and security systems in houses is a passive system that detects infrared energy. In order to make a sensor that can detect a human being, the sensor must be sensitive to the temperature of a human body. Humans, having a skin temperature of about 93 degrees F., radiate infrared energy with a wavelength between 9 and 10 micrometers. Therefore, the sensors are typically sensitive in the range of 8 to 12 micrometers.
The design of a bathroom, and its corresponding plumbing fixtures, must account for the use of both hot and cold water, in significant quantities, for cleaning the human body. From a decorating point of view the bathroom presents a challenge. Ceiling, wall, plumbing fixtures, and floor materials and coverings should be impervious to water and readily and easily cleaned. The use of ceramic or glass, as well as smooth plastic materials, is common in bathrooms for their ease of cleaning Such surfaces are often cold to the touch, however, and so water-resistant bath mats or even bathroom carpets may be used on the floor to make the room more comfortable.
Bathroom lighting should be uniform, bright and must minimize glare, especially in proximity to sinks, mirrors, toilets, urinals, and showers. For all the activities like shaving, showering, grooming etc. one must ensure equitable lighting across the entire bathroom space. The toilet should provide illumination for judging proximity to the perimeter of the toilet seat. The mirror area should definitely have at least two sources of light at least 1 feet apart to eliminate any shadows on the face. An undesirable effect of poor lighting causes skin tones and hair color are highlighted with a tinge of yellow. Actuating functional or aesthetic lighting in proximity to these plumbing fixtures is not always obvious.
U.S. Pat. No. 5,136,476 to Horn and titled Toilet Bowl Illuminator discloses a portable illuminator for illuminating toilet bowls. The disclosed illuminator hangs on the rim of a toilet bowl and a battery pack or other external power source carries current to a light source suspended within the bowl. Light sensitive and manual switches and current-regulating circuitry are options for the disclosed illuminator. The illuminator provides continuous illumination of provide guidance to a toilet bowl in an otherwise darkened room.
Even though the above cited bathroom fixtures and motion detectors meet some of the needs of the market, a device for actuating a light source on a proximal area of a bathroom fixture is still desired.